Counters

Detailed Description

Manipulate the numeric content of a document.

Counter operations treat the document being accessed as a numeric value (the document should contain a parseable integer as its content). This value may then be incremented or decremented.

Functions
lcb_STATUS	lcb_respcounter_status (const lcb_RESPCOUNTER *resp)
lcb_STATUS	lcb_respcounter_error_context (const lcb_RESPCOUNTER *resp, const lcb_KEY_VALUE_ERROR_CONTEXT **ctx)
lcb_STATUS	lcb_respcounter_cookie (const lcb_RESPCOUNTER *resp, void **cookie)
lcb_STATUS	lcb_respcounter_cas (const lcb_RESPCOUNTER *resp, uint64_t *cas)
lcb_STATUS	lcb_respcounter_key (const lcb_RESPCOUNTER *resp, const char **key, size_t *key_len)
lcb_STATUS	lcb_respcounter_mutation_token (const lcb_RESPCOUNTER *resp, lcb_MUTATION_TOKEN *token)
lcb_STATUS	lcb_respcounter_value (const lcb_RESPCOUNTER *resp, uint64_t *value)
lcb_STATUS	lcb_cmdcounter_create (lcb_CMDCOUNTER **cmd)
lcb_STATUS	lcb_cmdcounter_destroy (lcb_CMDCOUNTER *cmd)
lcb_STATUS	lcb_cmdcounter_parent_span (lcb_CMDCOUNTER *cmd, lcbtrace_SPAN *span)
lcb_STATUS	lcb_cmdcounter_collection (lcb_CMDCOUNTER *cmd, const char *scope, size_t scope_len, const char *collection, size_t collection_len)
lcb_STATUS	lcb_cmdcounter_key (lcb_CMDCOUNTER *cmd, const char *key, size_t key_len)
lcb_STATUS	lcb_cmdcounter_expiry (lcb_CMDCOUNTER *cmd, uint32_t expiration)
lcb_STATUS	lcb_cmdcounter_delta (lcb_CMDCOUNTER *cmd, int64_t number)
lcb_STATUS	lcb_cmdcounter_initial (lcb_CMDCOUNTER *cmd, uint64_t number)
lcb_STATUS	lcb_cmdcounter_durability (lcb_CMDCOUNTER *cmd, lcb_DURABILITY_LEVEL level)
	LCB_DEPRECATED2 (1 lcb_STATUS lcb_cmdcounter_cas(lcb_CMDCOUNTER *cmd, uint64_t cas), "CAS is not applicable to arithmetic operations")
lcb_STATUS	lcb_cmdcounter_timeout (lcb_CMDCOUNTER *cmd, uint32_t timeout)
lcb_STATUS	lcb_counter (lcb_INSTANCE *instance, void *cookie, const lcb_CMDCOUNTER *cmd)

Typedefs
typedef struct lcb_RESPCOUNTER_	lcb_RESPCOUNTER
	Schedule single counter operation. More...
typedef struct lcb_CMDCOUNTER_	lcb_CMDCOUNTER

Typedef Documentation

lcb_RESPCOUNTER

typedef struct lcb_RESPCOUNTER_ lcb_RESPCOUNTER

Schedule single counter operation.

Stability

Committed:

Parameters

instance	the instance
cookie	the pointer to associate with the request
cmd	the command to use

Returns

LCB_SUCCESS on success, other error on failure

Request

lcb_CMDCOUNTER* cmd;
lcb_cmdcounter_create(&cmd);
lcb_cmdcounter_key(cmd, "counter", strlen("counter"));
lcb_cmdcounter_delta(cmd, 1); // Increment by one
lcb_cmdcounter_value(cmd, 42); // Default value is 42 if it does not exist
lcb_cmdcounter_expiry(cmd, 300); // Expire in 5 minutes
lcb_counter(instance, NULL, cmd);
lcb_wait(instance, LCB_WAIT_NOCHECK);

Response

lcb_install_callback(instance, LCB_CALLBACKTYPE_COUNTER, counter_cb);
void counter_cb(lcb_INSTANCE *instance, int cbtype, const lcb_RESPBASE *rb)
{
    const lcb_RESPCOUNTER *resp = (const lcb_RESPCOUNTER *)rb;
    lcb_STATUS = lcb_respcounter_status(resp);
    if (rc == LCB_SUCCESS) {
        char* key;
        size_t key_len;
        uint64_t value;
        lcb_respcounter_value(resp, &value);
        lcb_respcounter_key(resp, &key, &key_len);
        printf("Incremented counter for %.*s. Current value %llu\n",
               key_len, key, value);
    }
}

Callback Errors

In addition to generic errors, the following errors may be returned in the callback (via lcb_respcounter_status):

• ::LCB_ERR_DOCUMENT_NOT_FOUND if the counter doesn't exist
• ::LCB_ERR_INVALID_DELTA if the existing document's content could not be parsed as a number by the server.